title: Three-dimensional ultrasound improves the accuracy of diameter measurement of the residual sac in EVAR patients.
abstract: OBJECTIVE
  Discrepancy between maximum diameters obtained with two-dimensional ultrasound and computed tomography (CT) after endovascular aneurysm repair (EVAR) is well known. The maximal diameter is ideally measured perpendicular to the centerline, a methodology so far only feasible with three-dimensional (3D) CT and magnetic resonance angiography (MRA). We aimed to investigate the agreement between 3D ultrasound and 3D CT and to determine reproducibility measures.
  
  
  METHODS
  Prospective study comparing 3D ultrasound with 3D CT in 124 consecutive patients seen 3 or 12 month after EVAR.
  
  
  RESULTS
  Replacing 2D with 3D ultrasound, the mean difference was improved from 6.0 mm to -1.3 mm (p < .001), and the range of variability was reduced from 9.4 mm to 6.6 mm (p = .009) using 3D CT as the gold standard. The mean difference between 3D ultrasound and 3D CT maximum diameter of the residual sac was -1.3 mm with upper and lower limits of agreement of 5.2 mm and -7.9 mm, respectively. Reproducibility measures of 3D ultrasound were ± 4 mm.
  
  
  CONCLUSIONS
  3D ultrasound correlate significantly better to 3D CT than the currently used 2D ultrasound method when assessing maximum diameter of the residual sac after EVAR, and reproducibility measures were within clinical acceptable values.
authors.affiliation: Department of Vascular Surgery, Rigshospitalet and University of Copenhagen, Denmark. Electronic address: kimbobank@yahoo.dk.
authors.forename: K
authors.initials: K
authors.lastname: Bredahl
authors.forename: M
authors.initials: M
authors.lastname: Taudorf
authors.forename: A
authors.initials: A
authors.lastname: Long
authors.forename: L
authors.initials: L
authors.lastname: Lönn
authors.forename: L
authors.initials: L
authors.lastname: Rouet
authors.forename: R
authors.initials: R
authors.lastname: Ardon
authors.forename: H
authors.initials: H
authors.lastname: Sillesen
authors.forename: J P
authors.initials: JP
authors.lastname: Eiberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000601:surgery*; D001027:Aortography / Q000379:methods; D019917:Blood Vessel Prosthesis Implantation; D057510:Endovascular Procedures; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional
keywords: 3D ultrasound; Abdominal aortic aneurysm; Computed tomography; Endovascular aneurysm repair; Interobserver variation